A known ski of this type French Pat. No. 1 304 880 consists either of a metallic hollow profile, in which a sheet-metal strip which extends longitudinally of the ski is supported for adjustment perpendicular to the running surface of the ski, or of two belts which are separated from one another by a layer of a rubber-elastic material. In both cases, in order to change the bending resistance of the ski, slotted bolts or cap nuts with a slot are provided and must be adjusted manually. Such an adjustment can easily lead to errors, since the snow conditions may possibly change during skiing. It is therefore practically impossible to at all times have the ski adjusted for the optimum value of the bending resistance of the ski.
According to Austrian Patent Application No. A 2633/83, the arch can be changed in a cross-country ski by the running coating or base being loosely supported on the ski member in the area of the middle third of the ski and being able to be moved away from the ski member by means of pressure screws.
In Austrian patent Application No. A 425/84 (corresponds to U.S. Ser. No. 700,259 filed Feb. 11, 1985), a cavity is provided in the cross-country ski and extends longitudinally of the ski, in which cavity a transverse beam is supported at its two ends. The transverse beam carries in its center a pin which is associated with a slide member equipped with a sloped surface. The abutment can be positioned to have a pregiven distance from the end of the pini, can engage the end of the pin, or can pretension the transverse beam through the pin. Depending on which of these three cases exists, the bending resistance or arch of the ski changes during the use of the ski.
However, the direction in which the ski adjusting mechanism should be adjusted is not indicated in these solutions. The correct adjustment of the ski is thus made difficult.